This invention relates generally to livestock care equipment, and more particularly to heater and thermostat arrangements for maintaining water in water-supply equipment at a pre-selected temperature.
Proper care of cattle or like farm animals requires that the farmer or animal husbandman provide a supply of clean water to the animals on a continuous and year-round basis. When animals are maintained in a pasture or feedlot, the farmer often finds it advantageous to provide water sources at specific locations, and to provide that water in specially designed watering devices.
One such device which has met with considerable commercial success is a well-type waterer described and claimed in U.S. Pat. No. 4,646,687. This watering device is insulated and covered so as to inhibit the contained water from freezing even during the protracted cold spells experienced in the Upper Midwest of the United States and elsewhere. A heater and thermostat arrangement can be provided in the waterer housing to maintain the water in an unfrozen and palatable state.
Modern agricultural animal husbandry is a highly complex commercial enterprise. Downward economic pressure on the price of livestock and livestock products such as milk, coupled with rising costs, require that the animal husbandman or farmer operate on increasingly thin margins of profit. Accordingly, the initial costs--and the operating costs--of any animal care equipment are of increasing importance to the farmer who is purchasing equipment, and to the manufacturer who is designing and making the equipment. To minimize the manufacturing cost of any waterer unit, the equipment manufacturer often utilizes electric resistance heaters of the caloric rod types. When intermittent heater operations can be used to maintain the water at a pre-selected temperature, inexpensive thermostats are often connected in electric series with these heaters.
One popular form of thermostat is that offered by the Essex Group of United Technologies, Inc. of Lexington, Ohio, as Type 414. This thermostat, and other inexpensive thermostats like it, is of the make-or-break variety. That is, electric contacts contained within the thermostat unit are closed by cooler temperatures so as to permit current to flow through the thermostat to the electric heater. When the water-containing trough or other thermally-sensed object warms up to a pre-selected temperature, the thermostat electric contacts separate, thereby breaking the circuit and halting electric current delivery to the heater. This contact make-or-break action is provided by mounting one of the contacts for cooperation with a bimetallic strip; temperature changes in the bimetallic strip cause contact movement between a contact and circuit open position and a contact and circuit closed position.
While these thermostats are inexpensive to manufacture, they are not always commercially available with close temperature tolerances. That is, the temperature required to move the contacts from a closed position to an open position may vary by as much as 15 degrees Fahrenheit between thermostat units made by the same manufacturer. Similar temperature variation may be present in the temperatures required to move the contacts from the open to the closed position.
It is, of course, necessary to maintain water in a watering trough in an ice-free unfrozen condition. This means that the heater and thermostat must operate to maintain the water at or above 32 degrees Fahrenheit at all times. When thermostats of the type described here are used, long heater cycle times are normally experienced. That is, when the thermostat contacts close and water heating action begins, heating continues for a relatively long period of time and the water is warmed to a relatively elevated temperature before the thermostat opens so as to halt heating action. Trough water temperatures of 60 degrees Fahrenheit have been encountered.
In the winter, water being delivered to a trough from a near-by well usually arrives at a temperature considerably below 60 degrees. This means that all incoming water must be heated by electricity supplied to the watering device in order to ensure against ice formation in the water trough. These long duty cycles and extensive water heating lead to increased operational cost for the animal husbandman.
But unless extended heating is provided, the long period of time during which the heater is turned off might permit the temperature within the incoming well water pipe to drop below freezing, thereby permitting the water in that line to freeze. Such freezing action could destroy the waterer and a frozen waterer can lead to livestock loss.
It is accordingly an object of the present invention to provide a thermostat and heater arrangement which will permit the heater to be operated in short duty cycles. That is, the heater can be turned on and off relatively rapidly, and the adjacent water can thereby be maintained at a relatively uniform temperature without wide temperature swings in the water. With these arrangements, the average water temperature can be reduced, and electric energy savings can be effected.
Another object is to provide a heater and thermostat arrangement especially designed for a trough-type waterer which is inexpensive yet effective, reliable and rugged. Yet another object is to provide an inexpensive yet effective, reliable and rugged system for mounting a heater and a thermostat to a water trough. A related object is to provide a mounting system which will permit the heater and thermostat to work effectively together so as to save energy.
Other objects and advantages of the invention will become apparent upon reading the following detailed description and upon reference to the drawings. Throughout the drawings, like reference numerals refer to like parts.